.preview {
    position: relative;
    height: 200px;
    background: url('../images/blog1.jpg') no-repeat 0 50%;
    background-size: cover;
}

.preview::after {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, .4);
}
.error-tips {
	position: relative;
    padding-top: 60px;
    height: 600px;
    text-align: center;
	background: #5a5d94;
}
.error-tips > img {
	margin: 0 auto; 
	height: 300px;
	display: block;
}
.error-tips > a {
	padding: 10px 20px;
	text-indent: 1em;
	color: #fff;
	font-size: 24px;
	display: inline-block;
	border:2px solid #fff;
	background: url(../images/home.png) no-repeat 5% 50%;
}